ATMOSPHERICAL OXIGETT, 219 



flice of wet fponge; it was then put under an inverted jar, 

 containing common air, and (landing in water. Tins plant 

 encreafed conliderably in bulk in the courfe of 20 days; be- 

 fides which it had taken root in the fponge; it was therefore 

 transferred into a jar filled with azote; but this change of cir- 

 cumftances put a flop to vegetation; for the herb made no fur- 

 ther advances, but withered away. 



Exp. 5. In order to diverfify thefe experiments as much as with plants in 

 poflible, I took a number of phials, having narrow necks, and ^^'^^ deprived 

 filled them with water, which was either procured from fnow, 

 or deprived of air by boiling. Proper plants being then placed 

 in the bottles, they were introduced quickly through water 

 into jars filled with azote; under which circumflances, all my 

 fpecimens died away fooner or later without making one effort 

 to vegetate. The herbs ufed on thefe occafions were the com- 

 mon garden fpear-mint and the draco-cephalum Moldavicum; 

 both of which vegetate freely in bottles of water ex})ofed to 

 the atmofphere. I alfo treated in the fame manner, a branch 

 of Lyfimachia vulgaris, which was ready to flower; it de- 

 clined gradually for a month, but never opened one blofTom; 

 though it is an aquatic plant and flowers very well in jars of 

 water. It may here be remarked once for all, that vegetables 

 die very flowly in azote, provided they are fupplied with water 

 deprived of air; but if my experiments may be relied on, all 

 their natural fiinflions ceafe in thefe circumflances, as foon as 

 they are removed from the atmofphere. 



Exp. 6. The lofs of energy experienced by plants confined Plaats^iem 

 ^ ... . , . . T r -^ . . . aaote for want o# 



in mephitic air, does not appear toarile from an injurious qua- (j^ej^ prope» 



lity of the gas, but from the want of the falutary ftimulusofftimulus. 

 oxigen; for a flip of fpear-mint, which had remained twelve 

 days in a glafs of azote, recovered upon being reflored to the 

 air, with the lofs of its loweft leaves only ; and an ofT-fet of 

 fempervivum vegetated freely after being removed from a jar 

 of the fame gas, in which I had kept it, from the 2nd of April 

 to the 2nd of May, flanding in a bottle of fnow water. Thefe 

 fa6ts feem to argue, that vegetables, treated in the manner de- 

 fcribed as above, fuffer a fpecies of torpidity, from which 

 they may be recalled by the prefence of atmofpherical air, pro- 

 vided the re-admifiion of this necefTary agent be not delayed 

 too long; in which cafe, the plant perifhes, in confequence of 



lh« 



4 



